No, but I would be taking both out now and disposing of them before other rhododendrons became affected.

Could the residue be from honeydue secreted by aphids from an overhanging tree? the buds are they dead through winter damage or lack of water? they need to be kept well watered through the summer whilst forming the flower buds, feed two/three weeks with ericacious feed, julien.

thanks for the advice. i will pass it on to her!